A hand scraper and a bit of elbow grease has taken the majority off
I think the zinc fumes will only come about at 907°, the boiling point of zinc and even is the gun was that hot, as Paul said, the metal won't be nearly that hot.I'd caution against using a heat gun on galvanised metal. Some of these heat guns can easily go to 600oC, which is getting pretty close to the melting point of zinc, and you really don't want to be around the zinc oxide fumes that might result from this. If I were you I'd try with mechanical or chemical means first.
I think the zinc fumes will only come about at 907°, the boiling point of zinc and even is the gun was that hot, as Paul said, the metal won't be nearly that hot.
It would probably work quite well to burn it off but it would need to be done outside on a windy day or with really good ventilation and a respirator because of the paint and possible zinc fumes.That's more like it. I got mixed up with the melting point of zinc which is less than half that at just over 400°C. However, it was probably still was worth mentioning as you can be sure that some numpty in future is going to try a heat gun and thinking 'this is a bit slow' will then go off to find something much hotter to burn the paint off with more quickly.